提出了一种在宇宙学模拟中跟踪超大质量黑洞生长和活动星系核反馈的方法。我们的模型是Springel et al.（2005）模型的一个重大修改版本。由于宇宙学模拟缺乏分辨率和物理模型的多相星际介质，他们往往大大低估了邦迪-霍伊尔吸积率。因此，为了使低质量的BH生长，有必要通过大的特设因子来增加稠密气体中的预测的Bondi-Hoyle速率。我们探讨的物理制度，使用这些因素是合理的，并通过这引入一个新的处方气体吸积。活动星系核的反馈是通过将吸积气体的静止质量能量的一部分热耦合到周围介质中来模拟的。我们描述的实施以及模型的局限性，并激励所有的变化相对于以前的工作。我们调查的鲁棒性的预测宇宙恒星形成的历史，红移零宇宙BH密度，BH标度关系，和星系特定的恒星形成率。我们发现，需要增加预测的吸积率，在文献中的标准程序，是最重要的不确定性来源的自由。我们的模拟表明，超大质量黑洞能够调节其增长，释放一个固定的能量为一个给定的晕质量，独立于假设的AGN反馈的效率，这套标准化的BH标度关系。无论BH种子最初是放置在BH缩放关系的上方还是下方，它们都生长到相同的关系上。AGN反馈有效地抑制了大质量星系中的恒星形成。
英文摘要：
(Abridged) We present a method that tracks the growth of supermassive black holes (BHs) and the feedback from AGN in cosmological simulations. Our model is a substantially modified version of the one by Springel et al. (2005). Because cosmological simulations lack both the resolution and the physics to model the multiphase interstellar medium, they tend to strongly underestimate the Bondi-Hoyle accretion rate. To allow low-mass BHs to grow, it is therefore necessary to increase the predicted Bondi-Hoyle rates in dense gas by large, ad-hoc factors. We explore the physical regimes where the use of such factors is reasonable, and through this introduce a new prescription for gas accretion. Feedback from AGN is modeled by coupling a fraction of the rest-mass energy of the accreted gas thermally into the surrounding medium. We describe the implementation as well as the limitations of the model and motivate all the changes relative to previous work.
We investigate the robustness of the predictions for the cosmic star formation history, the redshift zero cosmic BH density, BH scaling relations, and galaxy specific star formation rates. We find that the freedom introduced by the need to increase the predicted accretion rates, the standard procedure in the literature, is the most significant source of uncertainty. Our simulations demonstrate that supermassive BHs are able to regulate their growth by releasing a fixed amount of energy for a given halo mass, independent of the assumed efficiency of AGN feedback, which sets the normalization of the BH scaling relations. Regardless of whether BH seeds are initially placed above or below the BH scaling relations they grow onto the same relations. AGN feedback efficiently suppresses star formation in high-mass galaxies.
Formation of galactic nuclei with multiple supermassive black holes at high redshifts
我们研究了由于星系在高红移时的高合并率而在贫气体星系核中形成的多个超大质量黑洞（SMBH）群。我们计算的相对可能性的二进制，三重和四重SMBH系统，考虑相关过程的时间尺度和合并树相结合的N-体模拟的恒星和SMBH在星系核的动态。现今典型的质量为$M_0\approx 10^{14}$ M $_\odot$的晕在$z\sim 6$处的平均质量为$M_{z=6}=5\times 10^{11}$ M $_\odot$，而当前质量为$M_0\gtrsim 10^{15}$ M $_\odot$的稀有晕在该红移处的平均质量为$M_{z=6}=5\times 10^{12}$ M $_\odot$。这些星系团大小的晕被认为是$z\sim 6$中单个星系的宿主。我们预计大约30%的星系中的晕与现今的质量$M_0\approx 10^{14}$ M $_\odot$包含两个以上的SMBH在红移$2\lesssim z\lesssim 6$。对于现今较大的晕，使用$M_0\gtrsim 10^{15}$ M $_\odot$，该分数几乎为60%。在高红移处存在多个SMBH可能解释在大质量椭圆星系的核心中观察到的质量不足，这些星系的质量是其中心BH的5倍。多个SMBH也会导致恒星的潮汐分裂率提高，与孤立的BH双星相比，修改了引力波信号，并以超过2000 km/s $^{-1}$的高速从星系中弹射SM…
Testing the evolutionary pathways of galaxies and their supermassive black holes and the impact of feedback from Active Galactic Nuclei via large multiwavelength datasets
The formation of supermassive black holes from Population III.1 seeds. IV. Self-regulated seeding from supermassive star ionizing feedback
Chalmers University of Technology（查尔姆斯理工大学）；INAF - Osservatorio Astronomico di Brera（意大利国家天体物理研究所布雷拉天文台）；University of Modena & Reggio Emilia（摩德纳与雷焦艾米利亚大学）；University of Oxford（牛津大学）；University of Memphis（孟菲斯大学）；Center for Astrophysics, Harvard and Smithsonian（哈佛史密松天体物理中心）；Università degli Studi di Trieste（的里雅斯特大学）；INAF - Osservatorio Astronomico di Trieste（意大利国家天体物理研究所的里雅斯特天文台）；INFN, Sezione di Trieste（意大利国家核物理研究所的里雅斯特分部）
The fundamental signature of star formation quenching from AGN feedback: A critical dependence of quiescence on supermassive black hole mass not accretion rate
Self-regulated growth of supermassive black holes by a dual jet/heating AGN feedback mechanism: methods, tests and implications for cosmological simulations
